Chromatographic Hydrophobicity Index (CHI)

2012 ◽  
pp. 377-414 ◽  
Author(s):  
Martí Rosés ◽  
Elisabeth Bosch ◽  
Clara Ràfols ◽  
Elisabet Fuguet
Keyword(s):  
Hydrophobicity Index

A conformation-dependent hydrophobicity index

1989 ◽  
Vol 7 (3) ◽  
pp. 181 ◽  
Author(s):  
NigelG.J. Richards ◽  
PhilipB. Williams ◽  
MichaelS. Tute
Keyword(s):  
Hydrophobicity Index

scholarly journals Aliphatic compounds, organic C and N and microbial biomass and its activity in long-term field experiment

2011 ◽  
Vol 51 (No. 6) ◽  
pp. 276-282 ◽  
Author(s):  
T. Šimon
Keyword(s):  
Microbial Biomass ◽  
Field Experiment ◽  
Basal Respiration ◽  
Aliphatic Compound ◽  
Hydrophobicity Index ◽  
Organic C ◽  
Aliphatic Compounds ◽  
C And N ◽  
Term Field

The content of aliphatic compounds, hydrophobicity index, organic C and N content and the microbial biomass and respiration activity were analysed in soil samples originating from different plots of a long-term field experiment (variants: nil, NPK – mineral fertilization: 64.6–100 kg/ha/year, FYM – farmyard manure and FYM + NPK) from three blocks (III, IV and B) with different crop rotation. Samples were taken from 0–200 mm layer in 2002 and 2003 (spring and autumn). The plots without any fertilization had the significantly lowest aliphatic compound content compared to variants fertilized by FYM or FYM + NPK in all the evaluated blocks in both years. The variants fertilized only by mineral NPK without any organic fertilization had the slightly increased aliphatic compound content but they did not exceed significantly the control variants in most cases. The aliphatic compound contents correlated significantly with the organic C contents in 2002 and 2003, as well. The values of the hydrophobicity index showed a similar trend like the data mentioned above. Organic manure increased the soil organic nitrogen content, similarly to the carbon content. In variants fertilized by FYM and FYM + NPK the higher microbial biomass content was found comparing to unfertilized variants. Correlations between aliphatic compound content and biomass differed in spring (2002: r = 0.065, 2003: r = 0.068) and autumn (2002: r = 0.407, 2003: r = 0.529). Organically fertilized variants had increased basal respiration, in autumn 2002 the basal respiration was higher in variants fertilized by mineral NPK, too. The highest specific respiration was recorded in the unfertilised plot in block B (autumn 2002 and 2003), where low microbial biomass exhibited high activity. Increased specific respiration was found also in plots fertilized by FYM and FYM + NPK (block III and IV, autumn samplings). Positive significant correlations between microbial biomass content and basal respiration were found in 2002 (spring: r = 0.716) and 2003 (spring: r = 0.765, autumn: r = 0.671).

scholarly journals Immobilized artificial membrane chromatography: from medicinal chemistry to environmental sciences

ADMET & DMPK ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 225-241 ◽  
Author(s):  
Fotis Tsopelas ◽  
Chrysanthos Stergiopoulos ◽  
Anna Tsantili-Kakoulidou
Keyword(s):  
Medicinal Chemistry ◽  
Environmental Science ◽  
Oral Absorption ◽  
Stationary Phases ◽  
Aquatic Organisms ◽  
Drug Candidate ◽  
Artificial Membrane ◽  
Hydrophobicity Index ◽  
Immobilized Artificial Membrane ◽  
Early Drug

Immobilized Artificial Membrane (IAM) chromatography constitutes a valuable tool for medicinal chemists to prioritize drug candidates in early drug development. The retention on IAM stationary phases encodes lipophilicity, electrostatic and other secondary interactions contrary to traditional octanol-water partitioning. An increasing number of publications in recent years have suggested that IAM indices, including isocratic log k(IAM) or extrapolated log kw(IAM) retention factors, chromatographic hydrophobicity index CHI(IAM) or the polarity parameter Δlog kw(IAM) can successfully model the passage of xeniobiotics through biological membranes and barriers and predict pharmacokinetic properties, often in combination with additional descriptors. Examples referring to the modeling of human oral absorption, blood-brain penetration and skin partition are described. More recently, IAM chromatography has been applied to estimate toxicological endpoints in regard to drug safety, such as phospholipidosis potential, or in regard to chemical risk hazards including the bioconcentration factor and aquatic organisms’ toxicity. The promising results in both medicinal chemistry and in environmental science in combination with the speed, reproducibility and low analyte consumption suggest that a broader application of IAM chromatography in the early drug discovery process and in ecotoxicity may save time and money in initial drug candidate selection and will contribute to a reduced risk hazard of chemicals.

scholarly journals Effects of High Intensity Ultrasound on Physiochemical and Structural Properties of Goat Milk β-Lactoglobulin

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3637
Author(s):  
Xinhui Zhou ◽  
Cuina Wang ◽  
Xiaomeng Sun ◽  
Zixuan Zhao ◽  
Mingruo Guo
Keyword(s):  
Thermal Stability ◽  
Structural Properties ◽  
High Intensity ◽  
Structural Changes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Goat Milk ◽  
High Intensity Ultrasound ◽  
Hydrophobicity Index ◽  
Β Lactoglobulin

This study aimed to compare the effects of high intensity ultrasound (HIU) applied at various amplitudes (20~40%) and for different durations (1~10 min) on the physiochemical and structural properties of goat milk β-lactoglobulin. No significant change was observed in the protein electrophoretic patterns by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Deconvolution and second derivative of the Fourier transform infrared spectra (FTIR) showed that the percentage of β-sheet of goat milk β-lactoglobulin was significantly decreased while those of α-helix and random coils increased after HIU treatment The surface hydrophobicity index and intrinsic fluorescence intensity of samples was enhanced and increased with increasing HIU amplitude or time. Differential scanning calorimetry (DSC) results exhibited that HIU treatments improved the thermal stability of goat milk β-lactoglobulin. Transmission electron microscopy (TEM) of samples showed that the goat milk β-lactoglobulin microstructure had changed and it contained larger aggregates when compared with the untreated goat milk β-lactoglobulin sample. Data suggested that HIU treatments resulted in secondary and tertiary structural changes of goat milk β-lactoglobulin and improved its thermal stability.

scholarly journals Computational Models for Structure-Hydrophobicity Relationships of 4-Carboxyl-2,6-Dinitrophenyl Azo Hydroxynaphthalenes

2007 ◽  
Vol 90 (1) ◽  
pp. 291-298 ◽  
Author(s):  
Olakunle S Idowu ◽  
Olajire A Adegoke ◽  
Abiola Idowu ◽  
Ajibola A Olaniyi
Keyword(s):  
Azo Dyes ◽  
Computational Models ◽  
Intramolecular Interaction ◽  
Liquid Paraffin ◽  
Hydroxyl Group ◽  
Computer Assisted ◽  
Organic Modifiers ◽  
Sunset Yellow ◽  
Hydrophobicity Index ◽  
Calculated Density

Abstract Some phenyl azo hydroxynaphthalene dyes (e.g., sunset yellow) are certified as approved colorants for food, cosmetics, and drug formulations. The hydrophobicity of 4 newly synthesized azo dyes of the phenyl azo hydroxynaphthalene class was investigated, as a training set, with the goal of developing models for quantitative structureproperty relationships (QSPR). Retention behavior of the molecules reversed-phase thin-layer chromatography (RPTLC) was investigated using liquid paraffin-coated silica gel as the stationary phase. Mobile phases consisted of aqueous mixtures of methanol, acetone, and dimethylformamide (DMF). Basic hydrophobicity parameter (Rmw), specific hydrophobic surface area (S), and isocratic chromatographic hydrophobicity index (o) were computed from the chromatographic data. The hydrophobicity index (Rm) decreased linearly with increasing concentration of organic modifiers. Extrapolated Rmw values obtained by using DMF and acetone differ significantly from the value obtained by using methanol as organic modifier P < 0.05, 1-way analysis of variance (ANOVA), Tukey's multiple comparison test. Structureproperty relationships showed that hydrophobicity was dependent on type and position of naphthalene ring substituents. Rm decreased with the presence of a highly polar substituent (e.g., COOH). Owing to intramolecular interaction, Rm increased when the common hydroxyl group (OH) is positioned ortho to the azo group, relative to para positioning, in 2 positional isomers. Pattern recognition data analysis underscores the utility of φo as a more accurate hydrophobicity descriptor than Rmw. φo is negatively correlated with theoretically calculated density, surface tension, and refractive index for the molecules. These models could be used to predict toxicity (absorption, distribution, metabolism, excretion, toxicity; ADMET) properties of the azo dyes and may also play useful roles in computer-assisted molecular discovery of nontoxic azo dyes.

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